From mboxrd@z Thu Jan 1 00:00:00 1970 From: "David S. Miller" Subject: Re: Tigon3 5701 PCI-X recv performance problem Date: Wed, 8 Oct 2003 13:32:48 -0700 Sender: netdev-bounce@oss.sgi.com Message-ID: <20031008133248.1583ddcf.davem@redhat.com> References: <3F844578.40306@sgi.com> <20031008101046.376abc3b.davem@redhat.com> <3F8455BE.8080300@sgi.com> <20031008183742.GA24822@wotan.suse.de> <20031008122223.1ba5ac79.davem@redhat.com> <20031008202248.GA15611@oldwotan.suse.de> <20031008132402.64984528.davem@redhat.com> <20031008203306.GB15611@oldwotan.suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: ak@suse.de, modica@sgi.com, johnip@sgi.com, netdev@oss.sgi.com, jgarzik@pobox.com, jes@sgi.com Return-path: To: Andi Kleen In-Reply-To: <20031008203306.GB15611@oldwotan.suse.de> Errors-to: netdev-bounce@oss.sgi.com List-Id: netdev.vger.kernel.org On Wed, 8 Oct 2003 22:33:06 +0200 Andi Kleen wrote: > Well, this thread was about the tigon3 and I don't see that as an el cheapo > card. If SGI uses it on the Altix I guess they want it to perform well > with many CPUs. It's one of the oldest variants of the tg3 chip and it's full of hardware bugs when used in PCI-X. > I personally think it's better to just use slab to implement it, > allocating pages doesn't seem to have any advantages to me. The page chunk allocator is meant to make it easier to put the non-header parts in the frag list of the SKB, see? It means we don't need to do anything special in the networking, all the receive paths handle frag'd RX packets properly. We can't take pages SLAB is using and attach them to the fraglist of the SKB, kfree_skb() is going to try and put_page() on them. If we used slab, we'd need to do something like: 1) skb->h.raw or whatever have special meaning and point to different buffers. 2) There's a skb->data2 or something like that. Both are a lot of work compared to my suggestion.